The acute respiratory distress syndrome (ARDS) is a severe, life-threatening disease process, which affects approximately 150,000 patients per year with an associated 30-50 percent mortality rate. Periluorocarbons are inert, colorless, low surface tension liquids that can carry large quantities of oxygen and carbon dioxide. Clinical studies are currently exploring the safety and effectiveness of Partial Liquid Ventilation (PLy), in which the periluorocarbon-filled lung is gas-ventilated, in the setting of ARDS. However, there are a number of features, which suggest that the very different technique of Total Liquid Ventilation (TLV), in which the lungs are ventilated with perfluorocarbon using a liquid ventilating device, will be more effective from a biophysical and physiologic perspective. Previously designed liquid ventilators have been complex, have required large volumes of the expensive pert fluorocarbon for priming, and were not suitable for clinical use or human trial testing. The current proposal is directed at developing a clinically suitable simplified liquid ventilator for testing, characterizing, and improving the mechanical and gas exchange properties and capabilities in-vitro, and subsequently in well established in-vivo large animal model. These data will be critical toward demonstrating the clinical relevance and thus the commercial feasibility of this device. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE